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Alameda County · California

Hayward ADU Fees in 2026

Every government fee we could verify for an ADU in Hayward, from official sources. Figures below are for an 800 sq ft ADU unless noted.

Every figure links to its official source document. Last verified 16 Oct 2026. Fees are re-verified on a rolling schedule (next full pass Dec 2026). Official fee schedule ↗ How we price →

Verified fees, 800 sq ft ADU

$13,411

across 3 line items

The 750 sq ft cliff

$3,812

impact fees at 751 sq ft — $0 at 750 sq ft by state law

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same data, any square footage

Fee table

Amounts computed for an 800 sq ft ADU from each item's published rate. "Exempt" lines are $0 by state law at this size.

FeeCategoryRate800 sq ftSource
School district developer fee (HUSD, residential)School fees$5.38/sq ft$4,304official doc ↗verified 16 Oct 2026
Park Dedication / Impact Fee — ADU (flat)Impact feesflat fee$3,812official doc ↗verified 24 Oct 2026
Sewer connection fee — ADU explicit line (per unit)Utility & capacityflat fee$5,295official doc ↗verified 16 Oct 2026

These are the line items we have verified so far — not a complete bill. Site-specific charges (utility laterals, soil work) vary by lot. How we price →

The 750 sq ft cliff in Hayward

At 751 sq ft, the impact fees above total $3,812. At 750 sq ft, state law (Gov. Code §66311.5) sets them to $0. One square foot can be worth $3,812 here — size your ADU accordingly.

What changes on January 1, 2027

Two state laws rewrite parts of this table. SB 1117 (Chapter 809) re-bases covered impact fees for up to two ADUs on only the square footage above 750 — at 800 sq ft, most impact-fee lines shrink to a 50 sq ft basis. School developer fees and water/sewer connection or capacity charges are not covered and do not change. AB 956 (Chapter 791) makes two detached ADUs per single-family lot a ministerial approval. Details: SB 1117 and the 750 sq ft cliff · AB 956: two ADUs on one lot

Common questions

Are impact fees waived for ADUs under 750 sq ft in Hayward?

Yes. California law (Gov. Code §66311.5) bars local agencies from charging impact fees on ADUs of 750 square feet or less. That applies in Hayward the same as everywhere else in California. At 751 sq ft, the impact fees we have verified for Hayward total $3,812 — the cliff is real here.

Where do these Hayward ADU fee numbers come from?

Every line item links to the official source document — the city or county fee schedule, the school district's developer-fee resolution, or the utility district's charges — with the date we last verified it. We publish no fee modeled, no fee guessed.

How much are school district fees for an ADU in Hayward?

$4,304 for an 800 sq ft ADU ($5.38/sq ft), per the district document linked in the table. Note: since January 1, 2026, ADUs under 500 sq ft are exempt from school fees under state law.

Calculate your exact fees → Read the Hayward cost breakdown →

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